Two-stroke explosion-motor



Patented July 9, 1 935 PATENT OFFICE 2,001,515 'rwo-srrnoxa nxrosroN-Mo'roa Alfred Lesage, Schweinfurt, Germany Application October 5,1934, Serial No. 746,946

- In Germany October 2, 1933 4 Claims iGl. 123-65) The invention relates.to a two-stroke cycle engine adapted for distribution by means of ports[and in which the admission openings are entirely or almostdiametrically opposed to the exhaust opening.

The object of the invention is to provide a thorough scavenging of thecylinder of the engine by means of fresh gases sweeping the interior ofthe cylinder in its entire area, thus obtaining a more perfect charge inabsence of burnt gases. ,This object is attained according to theinvention by admitting the'scavenging gaseous'mixture delivered" out ofthe crank case in two parallel streams obliquely directed towards thecylinder head through a conduit which is divided to form twoportsreduced in cross section near the entrance in order to acceleratethe velocity of the gases but enlarged thereafter, the streams thusbeing spread in some degree. A further characteristic consists in theprovision of the discharge port which is comparatively large verti callyto the axis'of the cylinder. In connection with the said disposition ofthe ports, the curved piston head will give the entering gas streams aspecial direction and inversion favorable for expellting the exhaustgases through the discharge P An'embodiment of the invention isdiagrammatically illustrated by way of example in the accompanyingdrawing, in which Fig. 1 is a longitudinal-sectional view of thecylinder and pertinentparts of an engine provided with the scavengingsystem according to the invention, and

Fig. 2 represents a cross sectional view on' the line IIII of Fig. 1.

The admission channel which communicates with the crank case andsisorifice by a partition 6 into two inone side tangentially to thecylinder wall. -The exhaust port is fully or nearly diametricallyopposed to the inlet nozzles and its lateral width is comparativelylarge and almost cor esponds to the distance of the outer walls of e twoadmission nozzles;

On account or this design a the distribution .haust port. In addition toLfor the fresh gases,

I which are uncovered towards the.

by means of inclinedparallelports the fresh gases pass through theadmission channel 4 into the cylinder in two parallel jets directedupwards in a slanting direction, which. jets arestill more deflectedupwards by the cylinder wall met by them above the discharge aperturewhere'they are combined and inverted as to their direction in the topportion of the cylinder so that they are at the same' time urged towardsthe centre of the cylinder on spiral paths and together directeddownwards to the exhaust port in a descending direction, therebyexpelling the exhaust gases through the discharge aperture -8.

This guide of the scavenging operation is further assisted by aprotrusion 9 of the piston head directed into the combustion chamber,such as a vaulted or roof-like head of the piston.

The scavenging operation produced by the fresh gases in the cylinderwhile the direction of the flow is inverted takes place withacceleration in nozzle-like admission ports whereas the dimensions ofthe exhaust port are such that the exhaust gases urged downwards areallowed to escape above the piston head almost over the full width ofthe cylinder. The inversion of the flow in the cylinderis obtainedpartly the admission ports being inclined upwards and partly by thepiston head being raised in'its central por-- tion so that also on theother side thereof the gases flowing off are directed towards the exthisthe nozzles are enlarged again behind their point of smallest width sothat the streams of gas entering tangentially and with increasedvelocity scavenge the interior of the whole cylinder and are not onlyurged upwards at the wall opposite to the admission port but alsopressed towards one another. In-this,,way thereis obtained a thoroughscavenging of the whole cylinder.

I claim:

1. In a two-stroke cycle engine, the combination with a cylinder, of apiston reciprocating therein, parallel admissionapertures inclined to-.

indlpiltonldlpted the lonzitudlnfl phne, an exhaustoppodtotonldlnletportlmdlnnldplane, to uncover and ports at the lowerend of its stroke, and having a head with mrl'acea extending from saidport: 'upwu-dly town-dz the'head end 01' said cylinder, whereby exfiaustport,tl 1e nxea 0t the hellcgs being substantially at right males to theaxis of the cylinder.

ALFRED LESAGE

